At present, a lot of herbicides have been put to practical use as those applicable to paddy fields, and they are popularly used as single products or combination products.
Herbicides may be applied to various kinds of paddy weeds. A lot of herbicides effective against annual broad-leaved weeds are known, and herbicides effective against perennial weeds are increasing in these several years.
However, since Echinochloa crus-galli, which is one serious paddy weed and which grows mostly in large areas of paddy fields, belongs to the same family of Gramineae as a paddy rice plant belongs to, herbicides which are effective against only, Echinochloa crus-galli, especially those that have grown tall, without injuring paddy rice plants at all are not almost known.
As the prior art relating to compounds which are similar to the compounds of the present invention with respect to their chemical structures, compounds having a glycolic acid amide moiety bonded to the 2-position of a benzothiazole ring have been disclosed in JP-A 54-154762, compounds having the same moiety bonded to a 5-membered aromatic mono-cyclic ring containing an oxygen atom or a sulfur atom along with from 1 to 3 nitrogen atoms have been disclosed in JP-A 55-147267, compounds having the same moiety bonded to the 5-position of a tetrazole ring have been disclosed in JP-A 56-86175, and compounds having the same moiety bonded to the 5-position of an isoxazole ring have been disclosed in JP-A 63-152367. However, compounds having a glycolic acid amide moiety bonded to a pyrazole ring, such as those of the present invention, are not known at all up to the present and are novel compounds.